Currently CalDAV and CardDAV services are unavailable. This also affects the web-based calendar and contacts features in Runbox 7 as they read data from those services. Sorry for any inconvenience caused.
Update: An automatic update to the Apache web server software caused a problem with the services’ connection to the databases that store data for them. This resulted in unexpected downtime, which was resolved with a re-installation of associated software libraries and a configuration change.